Just after 2pm, residents of the Warri area, particularly those on Fox's Elbow Road, Watsons Road and Butmaroo Road, were being urged to enact their bushfire survival plans and if their plan is to leave, to leave now towards Bungendore.

Those in Braidwood, Bombay, Little Bombay, Mount Elrington, Wallaces Gap, Jembaicumbene Creek, Bendoura, Majors Creek, Reidsdale, Hoskinstown, Rossi, Forbes Creek and Butmaroo were being told to monitor the situation and follow advice from firefighters.

Read more: Bawley Point residents watch from beach as fire hits town

NSW Rural Fire Service spokesman Daniel Osbourne said the fire on the northern side near Warri had intensified and there were a number of properties that could be under threat.

Firefighters, aircraft and heavy machinery were positioned in that area for property protection, he said, and the Large Air Tanker had dropped two loads of retardant to help limit the spread of the fire.

"We're also seeing increased activity on the southern part of the fire, north of Harolds Cross locality in the Vernelly Road and Fork Road areas, and that fire continues to burn in a southerly direction," he said.

Crews in that area were undertaking tactical back-burning operations to help contain the spread of fire.

Backburning in that southern area was due to take place overnight, but weather conditions hampered efforts.

"It wasn't very successful due to the short window of opportunity," Mr Osbourne said.

"We are seeing very variable weather conditions with the wind, and different winds influencing and affecting the fire ground and driving fire behaviour."

He said there was low humidity and that was also having an impact.

"We did expect to see increased fire activity through the day [on Saturday] but probably not to this extent. It's indicative of severe drought conditions that are currently gripping the state."

Land owners along the north-western edge of the fire in the Tallaganda National Park took advantage of calmer conditions earlier on Saturday to back burn in an effort to prevent the fire further spreading towards Bungendore.

Peter Brasser, who owns Gidleigh Station about 10 kilometres south-east of Bungendore, said he had been working through the night alongside other property owners and volunteers to patrol the fire where the national park meets his farm.

"We've had 20 trucks lined up along here with people keeping an eye on the fire," Mr Brasser said.

He said the forest had not burned since the mid-1950s, which had led to a large fuel build-up. He praised the NSW National Parks for allowing a back-burning operation in tough conditions but said it was important to invest in more fire breaks.

The back-burning effort was designed to prevent the fire spreading further towards Bungendore, with a break in place between the national park and open paddocks, he said.

"It would be a much bigger fire, a major fire, without the back burning."

It has been a continuous effort to patrol the fire's edge, with the calmer conditions earlier on Saturday allowing Mr Brasser his first chance in over a week to relax slightly.

"We've been working to 4 o'clock in the morning and coming back at 6am. I didn't get any sleep for four days," he said.